Concurrent wireless/landline interface apparatus and method

ABSTRACT

An apparatus for interfacing at least one landline telephone service, at least one wireless cellular-type telephone service, at least one cellular-type wireless telephone and at least one standard telephonic type communication device through standard building interior telephone cable.

BACKGROUND AND PRIOR ART

[0001] The present invention relates to a system which integrates astandard telephonic type communication device, a cellular-type wirelessservice, a cellular interface system such as described in U.S. Pat. No.4,658,096, issued Apr. 14, 1987 to West et al., existing telephonewiring installed within a building, and a telephone company wirelineservice. In particular, the standard telephonic type communicationdevice, when connected to the invention, is capable of selectively bothreceiving and initiating calls over the cellular type wireless serviceas well as also both receiving and initiating calls over the telephonecompany wireline service.

[0002] Known cellular interface products such as the Telular Phonecell™,PCS^(one)™, of Telular Corporation, Buffalo Grove, Ill., and competingproducts from other companies, had difficulty in being connected to oneor more telephone extensions located in other areas of a building remotefrom the interface. The Telular PCS^(one)™ System shown pictorially inFIG. 1, is a combination charging circuit and docking station forhand-held cellular transceivers such as the Motorola MICRO-TAC™transceiver which allows the coupling of a standard telephone typecommunication device, such as a facsimile, modem, plain old telephone(POT) or any other device that would normally be coupled to a standardtelephone wall jack. Connection of more than one telephone extension atseparate locations within the building disadvantageously required thatseparate wiring be installed in the building or required a trainedinstaller to rewire the existing installed telephone wiring of abuilding, often with unsatisfactory results. After this installation orrewiring effort, two single line standard telephones were necessary toaccess both the telephone company and cellular-type service (cellular).A two line telephone would be required if a single instrument would beused to access both the telephone company (telco) wireline service aswell as the cellular interface line. When an incoming or outgoing callwould occur, there was often confusion as to whether the telco serviceor the cellular service was being accessed.

[0003] In addition, with the known cellular interface a consumer oftenmade a mistake in the installation of this type of product by notreading the manual and incorrectly plugging the cellular interfacedirectly into the telco service line. This was in violation of FederalCommunications Commission (FCC) Part 68 rules and invited possibledamage to the cellular interface and to the telco equipment. Knowncellular interfaces were difficult to be installed by individualspossessing no technical knowledge of electricity or of the telephonesystem. Each building is different as to whether it has telco line 1wiring installed, telco line 2 wiring installed, wiring shorts betweenwires on telco line 1 or line 2, an active Telco line 1, or an activeTelco line 2. Because of all these variables, there was difficulty forthe consumer to effectively and consistently be able to properly installa known cellular interface in a dwelling without a large number ofconsumer problems, and perhaps significant numbers of damaged cellularinterface devices. Prior art interfaces lacked adaptive intelligence andsystem diagnostics to sense the unique environment into which it wasinstalled and properly react to it Although prior art cellularinterfaces allowed a standard telephonic type communication device to beconnected to cellular service, prior art interfaces disadvantageouslydid not allow a standard telephonic type communication device to beselectively switched between wireline and cellular service. Prior artinterfaces had no provision for connection to a wireline telephonecompany service.

[0004] This invention is directed at solving these and otherdisadvantages of the prior art.

OBJECTS OF THE INVENTION

[0005] An object of the invention is to allow a facility, normally wiredfor a single telephone line from the wireline telephone company, tobecome a two-line facility, with the second line coupled to a wirelesscommunication system and remain fully compatible with all FCC Part 68devices, including standard telephones, (both, single and double line),facsimile devices, alarm systems and modems.

[0006] Another object of the invention is to allow a consumer withoutany tools or knowledge of a telephone system to use the invention byeasily allowing him to use his standard house telephone wiring and add acellular communication capability as an additional line to his currentsystem without improperly coupling an active device to a landlinetelephone outlet.

SUMMARY INVENTION

[0007] Accordingly, in accordance with an illustrative embodiment of thepresent invention, there is provided a telephonic communication systemhaving at least one communication device for interconnection with atelephone network via at least two communication media, the improvementcomprising means for coupling the at least one communication device withthe at least two communication media, and means for individuallydetermining the availability of each of the at least two communicationmedia, and means responsive to the determining means connected to thecoupling means for automatically interconnecting the at least onecommunication device with the telephone network via the available one ofthe communication media.

[0008] In accordance with another illustrative embodiment of the presentinvention, there is provided a communication system having first andsecond communication paths and at least one telephonic typecommunication device, the system being coupled to at least twocommunication networks for providing a first and second means ofcommunication, said first means of communication coupled to the firstcommunication path, and the communication system having at least onemeans for coupling the at least one telephonic communication type deviceto said first communication path, the improvement being means betweensaid at least one telephonic type communication device and said couplingmeans for connecting said telephonic type communication device to saidsecond communication path, and switching means coupled to said secondcommunication path and to said first and second means of communicationfor selectively coupling said second communication path to one of saidfirst and second means of communication.

[0009] In accordance with yet another illustrative embodiment of thepresent invention, there is provided a communication system having acommunication path and at least one telephonic type communicationdevice, the communication system being coupled to a communicationnetwork for providing a means of communication, and the communicationsystem having at least one telephonic communication type device coupledto said communication path, the improvement being testing means coupledto said communication path for testing the presence of any signalthereon, and interface means coupled to said communication path and saidtesting means and being responsive to said testing means for couplingsaid communication path to said communication network.

[0010] In accordance with still another illustrative embodiment of thepresent invention, there is provided a communication system comprising acellular type interface coupled between a cellular-type transceiver anda six position wall jack coupling means with at least four positionshaving individual conductors coupled thereto, a telephonic type devicecoupled to at least two of said individual conductors, and means coupledbetween said telephonic type device and said six position telephone jackcoupling means for inverting the position of at least two of saidindividual conductors to the position of two of the other individualconductors.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011]FIG. 1 is a pictorial diagram of a prior art cellular interfaceconnected to a standard telephonic type communication device.

[0012]FIG. 2 is a simplified pictorial prior art diagram of a wirelinetelephone company central office, a customer's building having fourconductor wireline telephone company cabling installed therein, and asingle line telephonic type communication device connected to two of thefour conductors.

[0013]FIG. 3 is a simplified diagram showing the connection of theinvention and of two standard telephonic type communication devices.

[0014]FIG. 4 is a block diagram of a prior art cellular interface.

[0015]FIG. 5 is a block diagram of the invention.

[0016]FIG. 6A is a detailed schematic diagram of the invention.

[0017] FIGS. 6B-6J are detailed schematic diagrams of portions of FIG.6A corresponding to blocks of FIG. 5.

[0018]FIG. 7 is a flow chart showing the operation of the inventionincluding the testing of the wireline telephone company's lines duringinitialization

[0019]FIG. 8 is a state diagram showing the operation of the inventionas controlled by software.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

[0020] Referring now to FIG. 2, a building 130 has been wired with afour conductor cable 160 for distributing a wireline telephone companyservice to a location within the building. The location has a sixposition telephone jack terminating the wireline telephone companyservice. FIG. 2 shows only one six position telephone jack 127 at onlyone location for simplicity; however, the building 130 has a pluralityof locations, each position has a six position telephone jack 127 suchas an RJ-11 jack for wireline telephone service termination. The servicefrom the wireline telephone company central office 104 is via a twoconductor cable 152 having a tip 154 and a ring 156 conductor. Referringto FIG. 3, the tip 154 and ring 156 conductors from the central office104 are connected to a service entrance terminal block 158. The fourconductor cable 160 of the building 130 is connected to the terminalblock 158. Two conductors 118 and 120 (usually with red and green wireinsulation) of the four conductors of the building cable are connectedto the tip 154 and ring 156 conductors from the central office 104. Theother two conductors 122 and 124 (usually with black and yellow wireinsulation), although connected to the service entrance terminal block158, are not used for communication with the central office 104 if thebuilding has only single telephone line service, such as a typicalsingle family residential dwelling. In addition to being connected tothe service entrance terminal block 158, the yellow 124 and black 122wires are also connected to a “line 2” position of the 6 positiontelephone jack 127 at each termination of wireline telephone servicewithin the building 130. Therefore, the black 122 and yellow 124conductors (ie line 2) of the building telephone cable 160 are availablefor interconnection between the invention and a plurality of standardtelephonic type communication devices, each device normally capable ofbeing coupled to a telco line (hereinafter “telephonic device”). Theinvention is simultaneously connected to both wireline and cellularservices. The invention is housed in a docking station similar to thePCS^(one)™ presently being manufactured by Telular Corporation.

[0021] Referring now to FIG. 3, the installation of the invention startsby directly plugging the invention into an available, typically wallmounted, six position telephone jack 127. The power supply is connectedto the system, and the power plug of the power supply is plugged into anavailable power outlet. All pre-installed single line telephone devicesare unplugged from the wall telephone jacks, a line inversion adapter130 is inserted into the telephone jack 127, and each single telco linetelephone device 108 is plugged into the line inversion adapter 130 orconversely, one or more telephone devices can also be left aspre-installed, as shown in FIG. 3. Single line standard telephonic typecommunication devices are designed to be plugged into the “line 1”position of six position telephone jacks. The line inversion adaptercauses the device to be connected to “line 2” of the telephone jack. Atelephone device 108 which is dedicated to the telco line does not usethe inversion adapter 130 at the wall telephone jack 127.

[0022] Upon being installed, the invention will perform a set of systemdiagnostics to determine if there are any problems with the installationenvironment. Determination of the electrical environment includes but isnot limited to: sensing if the unit telephone receptacle is connected tothe external wiring; sensing if the external wiring has a functioningconnection to a central office on Line 1; sensing if the external wiringhas a functioning connection to a central office on Line 2; and sensingwhether standard telephone devices are connected to Line 2. Systeminstallation problems' are displayed as codes on a display of a portablecellular telephone placed in the docking station of the housing.Interpretation of these error codes is in a user's manual.

[0023] Upon performing an installation successfully, calls can bereceived and placed on both the telco service and cellular service.Placing an outgoing call is accomplished normally by picking up thetelephone receiver and dialing. The invention has different sets ofcriteria which can be used to determine whether it will default to thetelco service or to cellular service. The criteria will vary dependingon how the unit is marketed and the service/customer which the unit isexpected to serve. For example, an internal electronic clock/calendarallows the defaulting to depend upon the time of day and day of week inorder to take advantage of differing telephone rates.

[0024] When a receiver of a telephone device is taken off hook with theinvention set to default to the telco service, and the user wants toplace a call on the cellular service, the user enters the cell code,preferably **C The invention then switches the telephone from the telcoline to the cellular line. An outgoing call is then placed normally. Ifthe unit defaults to the cell service and the user wishes to place acall on the telco service, the user enters the telco code, preferably**T. The call is then placed normally.

[0025] An incoming call on the telco line rings normally and is answeredby just picking up the receiver. An incoming call on the cellular linehas a slightly different ring characteristic (preferably it is twobursts during the two second ring period followed by a four second offtime). Because the telephone rings with these two differentcharacteristics, the person answering the call can tell in advance whichline is ringing. If a call is received on the telco line and is answeredand shortly thereafter a call is received on the cellular line, a callwaiting beep is heard in the telephone receiver. If the person using thetelephone performs a hook flash on the switch-hook of the telephoneinstrument, the telco line is placed on hold by the invention and thecellular line is connected to the telephone instrument. If a hook flashis again performed on the switch-hook of the telephone, the telco lineis reconnected and the cellular line is placed on hold. The samesequence of events applies if the initial call is received on thecellular line instead of the telco line. If a call is in progress on thecellular line and a telco line call is being received (as evidenced bythe telco line ringing,) a beep is heard through the telephone receiver.A hook flash puts the cell line on hold and connects the telco line. Theportion of the operation of the invention not fully disclosed herein isdescribed in the aforesaid U.S. Patent to West et al., which is herebyincorporated by reference. TABLE 1 Event Name General Description. OffHook Receiver of POTS device has been taken off the hook. Hang UpReceiver of POTS device has been placed on the hook. DialTone Dial tonehas been detected on the telco line. No Dial Tone No dial tone has beendetected on the telco line. Telco Ring Detected the POTS device ringingfrom incoming telco call. No Telco Ring POTS device stopped ringing fromincoming telco call. Cel Alert Incoming call from the cellular radio.Digit Entry Digits entered from the POTS device. Dial Complete Outgoingcaller has completed dialing. Cel Code Sequence of digits (**C) toswitch from telco line to cel line. Telco Code Sequence of digits (**T)to switch from cel line to telco line. Lost Telco The telco line haslost its connection. Hook Flash Momentary pressing (hang up) of POTSdevice receiver hook. Cel Not Inuse The called party on the cellularline has hung up.

[0026] The Off Hook event as described in Table 1 is detected bymonitoring loop current on either the telco line or the cellular linedepending on which is switched in. (The cel line is normally switchedin.) This is done by software stored in Read Only Memory (ROM) internalto a microprocessor detecting an active low signal on the Telco LC (U3port P3.0) when on a telco line, or Cel LC (U3 port P3.5) when on acellular line. The software does not recognize an off hook event unlessloop current had been absent (on hook) for more than 700 msec and thenloop current became present for at least 500 msec. The software switchesthe invention from the cellular line to the telco line through hardware(U3 port P.1), where cellular line is active high, and telco line isactive low.

[0027] The Hang Up event as described in Table 1 is detected bymonitoring loop current on either the telco line or the cellular linedepending on which is switched in. This is done by software detecting anactive low signal on the Telco LC (U3 port P3.0) when on telco line, orCel LC (U3 port P3.5) when on cellular line. Software does not recognizea Hang Up event unless loop current had been present (off hook) for morethan 500 msec and then an absence of loop current occurred for at least700 msec.

[0028] The Dial Tone event as described in Table 1 is detected bysoftware monitoring the hardware dial tone input at U3, port P3.7.Software must look for a sequence of transitions on this port thatrepresent a pattern created by a superimposed 350 Hz with 440 Hz signalproduced by zero crossing detection. Software does not recognize theDial Tone Event unless this signal is present for at least 500 msecwhile the Off hook condition is true and connected to the telco line(active low asserted on U3, port P2.1.).

[0029] The No Dial Tone event as described in Table 1 is detected bysoftware monitoring the hardware dial tone input at U3 port P3.7.Software must look for a sequence of transitions on this port thatrepresent a pattern created by a super imposed 350 Hz with 440 Hzsignal. Software does not recognize the No Dial Tone Event unless thereis an absence of this signal for at least one second while the Off hookcondition is true and connected to the telco line.

[0030] The Telco Ring event as described in Table 1 is detected bysoftware monitoring the hardware signal input at U3 port P3.4. Softwarerecognizes the Telco Ring Event by transitions on this port produced bya the ring signal (between 15 and 65 Hz) for at least 100 msec.

[0031] The No Telco Ring event as described in Table 1 is detected bysoftware monitoring the hardware signal input at U3 port P3.4. Softwaredoes not recognize the No Telco Ring event, unless the Telco Ring eventhas first been detected. When the Telco Ring event is detected, the NoTelco Ring event may be detected by the absence of the ring signal at U3port P3.4 for at least 5 seconds.

[0032] The Cel Alert event as described in Table 1 is detected bysoftware receiving a cell alert message from the cellular telephone viaserial transmission.

[0033] The Cel Alert, the Digit Entry event, and the Dial Complete eventare well known in the prior art.

[0034] The Cel Code event as described in Table 1 is detected bysoftware recognizing a sequence “**C” dialed.

[0035] The Telco Code event as described in Table 1 is detected bysoftware recognizing a sequence “**T” dialed.

[0036] The Lost Telco event as described in Table 1 is detected by thesoftware of the invention. The software recognizes a telco connection byasserting an active high on the hardware telco hold line through U3,port P2.0 and checking that telco loop current is present (active low oninput U3, port P3.0). If telco loop current is not present aftersoftware asserts an active hold, then software detects the Lost Telcocondition.

[0037] The Hook Flash event as described in Table 1 is detected bymonitoring loop current on either the telco line or the cellular linedepending on which is switched in. This is done by software detecting anactive low signal on the Telco LC (U3 port P3.0) when on the telco line,or Cel LC (U3 port P3.5) when on cellular line. Software does notrecognizes the Hook Flash event unless loop current had been present(off hook) for more than 500 msec and then an absence of loop currentoccurred for at least 200 msec, but no more than 700 msec.

[0038] The Cel Not Inuse event as described in Table 1 is detected bysoftware receiving the message from the cellular radio via serialtransmission and is well know in prior art.

[0039] The invention shown in FIG. 4 interfaces a cellular telephone 212to a telephonic device 108 and it allows the telephonic device 108 toaccess communications via the cellular telephone 212. The inventionconnects to a cellular telephone 212 via a cellular telephone interface204. The cellular telephone interface 204 is the actual physicalconnection which interfaces the cellular telephone 212 to the invention,and also connects to a telephonic device 108 via 208 the telco lineinterface. All the necessary information and power to the cellulartelephone is received and/or supplied through the cellular telephoneinterface 204.

[0040] Once power is applied to the invention, communication isestablished between the cellular telephone 212 and the CPU interface201. It uses a microprocessor, preferably an Intel 8051 type, to performall its operations such as initializing the cellular telephone 212,setting all of the control signals (I/O s) to their initial states for aringer circuit 203, and a receive and transmit circuit 206. The softwareis written in 8051 assembly language. All functions of the unit iscontrolled by CPU interface 201. The CPU interface 201 communicates withthe cellular telephone 212 via 204 and controls the necessary hardwareon board. This initializing is started by the Watchdog Timer & Resetcircuit 200 which is the circuit that jump starts the operation of allthe intelligence embedded into the system, it will restart the operationof all the intelligence if it detects an improper state of the externalhardware and/or internal timing sequences. During initialization, theCPU interface 201 sets all the necessary I/Os of the microprocessor totheir default conditions required by the external hardware to functionproperly. The telephone interface 208 is preferably an FCC part 68compatible RJ-11. At this point, if the telephonic device 108 connectedto the telephone interface 208 were to be taken offhook a precisionstandard dial tone would be received by the telephonic device.

[0041] If a call were to be made using the telephonic device 108 thefollowing would take place:

[0042] When telephonic device 108 connected at telephone interface 208comes offhook, a Battery Voltage circuit 210 provides the necessarypower required to operate the telephonic device 108. Since thetelephonic device 108 receives power, its offhook state will be detectedby an onhook & offhook detect circuit 207. It detects the Onhook/Offhookcondition of the telephonic device 108. This circuit also allows the CPUinterface 201 to evaluate pulse dialing activity.

[0043] Onhook offhook detect circuit 207 will report this condition ofthe telephonic device 108 to the CPU interface 201. Once CPU interface201 acknowledges the offhook condition it will generate a precision dialtone and inject it to receive and transmit circuitry 206. It interfacesthe receive and transmit signals from the telephonic device 108 to thereceive and transmit circuitry of the cellular telephone 212 in order tonotify the telephonic device 108, that it can initiate dialing activity.

[0044] Upon reception of dial tone, digits can be dialed in twodifferent formats:

[0045] First, DTMF (dual tone multi frequency) commonly known astouch-tone dialing, in which case the tones will be inputted to a DTMFdetection circuit 202 via the receive and transmit circuit 206. The DTMFdetection circuit will evaluate the digits dialed and determine theirvalues, and relay this information to the CPU interface 201.

[0046] Second, Pulse dialing which is an older method of dialingactivity, will be detected by the onhook & offhook detect circuitry 207.The digit information will then be relayed to the CPU interface 201.

[0047] The CPU interface 201 will take the digit signals received andwill convert them into serial digital information that could beunderstood by the cellular telephone 212. Once converted, theinformation will be relayed to the cellular telephone 212 with theappropriate command which will allow the cellular telephone 212 toaccess the cellular service provider through cell site 100 in order toestablish a communications link with the called party.

[0048] When the called party answers the call, a communications pathwill be established. The data or voice information between thetelephonic device and the called party will be relayed by the receiveand transmit audio circuit 206.

[0049] This established link can be terminated two ways:

[0050] First, the called party can hang up. This is usually referred toas the remote hang up. In this case the cell site 100 will notify thecellular telephone 212, and the cellular telephone will relay theinformation to the CPU interface 201. Upon receiving this informationthe CPU interface 201 will simply set all the external circuitry as if ahang up occurred at the local telephonic device 108.

[0051] Second, the calling party hangs up. This is usually referred toas the local hang up. In this case the CPU unit 201 is informed by theonhook & offhook detection circuit 207 that the telephonic device 108has been hung up. The CPU interface 201 will in turn relay this messageby sending an appropriate “end of call” message that is valid for theparticular cellular telephone 212.

[0052] If a call were to be received by the cellular telephone interfaceunit the following would take place:

[0053] The cellular telephone 212 would be notified by the cell site 100that it is being paged by the cellular communication system. Thismessage will be relayed to the CPU interface 201, which in turn willactivate the ringer circuit 203. Once the CPU informs this circuit thatthere is an incoming call, the unit will ring a telephonic device 108connected to the telephonic interface 208. This ringer signal is theninjected to the telephonic device 108 via telephonic interface 208. Thetelephonic device 108 will ring and the user would have to take thetelephonic device 108 offhook. Upon noticing that the telephonic device108 has been taken offhook, the onhook & offhook detect circuit 207 willnotify the CPU interface 201 which then will send the appropriate callanswer message for the communication device in use, thereby enabling acommunications link with the calling party.

[0054] A power generation circuit 209 supplies the necessary power forthe cellular telephone 212 to function. The power from the powergeneration circuit 209 is relayed to the cellular telephone 212 viacellular telephone interface 204.

[0055] The general system control flow is depicted by the state diagramin FIG. 8. An Initialize State 800 is in effect when the system is resetor initially turned on. During the Initialize State 800, communicationlines are monitored to verify that appropriate connections exist inorder to support product functionality. If the connections are correct,an Idle State 802 becomes active. If the connections are not correct, orsome non recoverable error occurs, then a Fatal Error State 801 becomesactive.

[0056] The Idle State 802 is the main state that occurs when the systemis ready and waiting for some event to occur. Events that will initiatea response while in the Idle State 802 are: the incoming Telco Ringevent, the Off Hook from the POTS device event, and the incoming CelAlert event The Telco Ring event will cause a Transition to a Ring WaitState 803. The Off Hook event will connect the telco line and cause atransition to the Off Hook State 804. The Cel Alert event will connectthe cellular line and cause a transition to a Cel Alert State 811.

[0057] The Off Hook State 804 becomes active whenever the Off Hook eventoccurs from the Idle State 802. While in the Off Hook State 804, thesystem checks for the presence of a telco dial tone from the telephonecompany indicated by the Dial Tone event and the No Dial Tone event. Ifthe system detects the telco dial tone, a transition is made to a TelcoDial State 805. If, however, the Dial Tone event is not detected, thesystem connects the cellular line, generates a cel dial tone(differentiated from the telco dial tone), and then transitions to a CelDial State 806.

[0058] The Telco Dial State 805 represent a condition where the systemis connected to the telco line, and the telephonic device is off hook.While in this state 805, the system will monitor and respond to one ofsix events: The Cel Alert event, the Digit Entry event, the DialComplete event, the Cel Code digit entry event, the Lost Telcoconnection event, and the Hang Up event. If the Cel Alert is detected,the system will momentarily connect the cellular line, sound a beep, andthen connect back to the telco line indicating to the user that there isan incoming call on the cellular line. If the Digit Entry is detected,the digit pressed is stored by the system in a digit buffer. If thedigit buffer contains the appropriate digits (such as **C), or if theLost Telco connection is detected, the system is then connected to thecellular line, the Cel Dial Tone is generated, and a transition is madeto the Cel Dial State 806. If the Dial Complete event occurs, indicatingthat the user has finished dialing, then a transition is made into aTelco Talk State 807. The Hang Up event will simply cause a transitionback to the Idle State 802. Any time a transition is made into the TelcoDial State 805 or the Cel Dial State 806, the digit buffer is cleared.The Cel Dial State 806 represent a condition where the system isconnected to the cellular line, and the POTS device is off hook While inthis state 806, the system will monitor and respond to one of sixevents: The Cel Alert event, the Digit Entry event, the digit DialComplete event, the Telco Code digit entry event, the Telco Ring event,and the Hang Up event. If the Cel Alert or the Dial Complete isdetected, the system will initiate a cellular send command andtransition to a Cel Talk State 808. If the Digit Entry is detected, thedigit pressed is stored by the system in the digit buffer. If the digitbuffer contains the appropriate digits (such as **T), the system is thenconnected to the telco line, and a transition is made to the Telco DialState 805. If the Dial Complete event occurs, indicating that the userhas finished dialing, then a transition is made into a Cel Talk State808. If the Telco Ring event occurs, the system will sound a beepindicating that an incoming call has been detected on the telco line.The Hang Up event will simply cause a transition back to the Idle State802.

[0059] The Telco Talk State 807 represents a state where a connection toanother party has been established on the telco line. This may occureither through an incoming call from the Ring Wait State 803, or throughan ongoing call from the Telco Dial State 805. While in the Telco TalkState 807, the system will monitor and respond to one of four events:The Hang Up event, the Lost Telco connection event, the Cel Alert Event,and the hook Flash Event. The Hang Up event will simply cause atransition back to the Idle State 802. If the Lost Telco connection isdetected, the system will connect the cellular line and check to see ifthere is a complete entry in the digit entry buffer meaning a number hadbeen dialed as an out going call. If the digit entry is complete, theentry is redialed on the cellular line and a transition is made to theCel Dial State 806. However, if a complete entry does not exists in thebuffer, then the transition is made to the Cel Dial State 806 and thecel dial tone is generated. If the Hook Flash event occurs, the telcoline is put on hold by the system, the cellular line is then connected,and a transition is made to a Telco Wait Cel Dial State 809. If the CelAlert is detected, the system will momentarily connect the cellularline, sound a beep, and then connect back to the telco Line and thencause a transition to a Telco Talk Cel Alert State 810.

[0060] The Cel Talk State 808 represents a state where a connection toanother party has been established on the cellular line. This may occureither through an incoming call from the Cel Alert State 811, or throughan ongoing call from the Cel Dial State 806. While in the Cel Talk State808, the system will monitor and respond to one of four events: The HangUp event, the Telco Ring event, the digit entry event, and the HookFlash Event. The Hang Up event will simply cause a transition back tothe Idle State 802. The Digit Entry event will be audibly produced orechoed to the user. If the Telco Ring event is detected, the system willsound a beep indicating an incoming call on the telco line andtransitions to Cel Talk Telco Ring State 815. If the Hook Flash eventoccurs, the telco line is then connected, and a transition is made to aCel Wait Telco Dial State 812.

[0061] The Cel Wait Telco Dial State 812 represents a state where aconnection to another party has been established on the cellular line,and the user has done a hook flash to dial out on the telco line withoutloosing the cellular party. Therefore this state 812 will respond toonly one of two events: The Digit Dial Complete event for dialinganother party, and the Hang Up event. The Hang Up event will simplycause a transition back to the Idle State 802. The Dial Complete eventwill cause a transition to a Telco Talk Cel Wait State 813.

[0062] The Telco Wait Cel Dial State 809 represents a state where aconnection to another party has been established on the telco line, andthe user has done a hook flash to dial out on the cellular line withoutlosing the telco line party. Therefore this state 809 will respond toonly one of three events: The Dial Complete event for dialing anotherparty, the Cel Alert event, and the Hang Up event. The Hang Up eventwill simply cause a transition back to the Idle State 802. If the DialComplete or the Cel Alert events occur, the system will initiate a sendcommand and will cause a transition to a Cel Talk Telco Wait State 814.

[0063] The Telco Talk Cel Alert State 810 represents a state where aconnection to another party has been established on the telco line, andthe Cel Alert has occurred. In this state 810, the system will respondto the Hook Flash event, the Hang Up event, and the Cel not Inuse event.The Hang Up event will cause a transition to the Cel Alert State 811.The Cel not Inuse event will cause a transition back to the Telco TalkState 807. If the Hook Flash is detected, the system will put the telcoline on hold, connect the cellular line, and make a transition into theCel Talk Telco Wait State 814.

[0064] The Cel Talk Telco Ring State 815 represents a state where aconnection to another party has been established on the cellular line,and the Telco Ring event has occurred. In this state 815, the systemwill respond to the Hook Flash event, the Hang Up event, the Digit Entryevent, the Lost Telco event, and the Telco Ring event. The Hang Up eventwill cause a transition to the Ring Wait State 803. If the hook Flash isdetected, the system connects the telco line, and makes a transitioninto the Telco Talk Cel Wait State 813. If the Telco Ring is detected,the system will sound a beep. If the Lost Telco connection occurs, atransition is made into the Cel Talk State 808. The Digit Entry eventwill cause the digit to be echoed on the telephonic device.

[0065] The Telco Talk Cel Wait State 813 represents a condition wherethe telco line is connected with an active party, and there is also aparty waiting on the cellular line. In this Telco Talk Cel Wait state813, the system will respond to the Hook Flash event, the Cel Not InuseEvent, and the Hang Up event. If the Hook Flash occurs, the telco lineis placed on hold, the cellular line is reconnected, and a transition tothe Cel Talk Telco Wait State 814 is made. If the Cel not Inuse eventoccurs, a transition is made to the Telco Talk State 807. If the Hang Upevent occurs, the system will reconnect the cellular line, begin ringingin order to re-establish connection with the party waiting on thecellular line, and make a transition to the Cel Alert State 811.

[0066] The Cel Talk Telco Wait State 814 represents a condition wherethe cellular line is connected with an active party, and there is also aparty holding on the telco line. In this state 814, the system willrespond to the Hook Flash event, the Lost Telco Event, and the Hang Upevent. If the Hook Flash occurs, the telco line connected and releasedfrom hold, and a transition to the Telco Talk Cel Wait State 813 ismade. If Lost Telco connection event occurs, a transition is made to theCel Talk State 808. If the Hang Up event occurs, the system will leavethe cellular line connected, begin ringing in order to re-establishconnection with the party waiting on the telco line, and make atransition to the Ring Wait State 803.

[0067] The Ring Wait State 803 represents a condition where thetelephonic device is hung up and ringing due to a party on the telcoline. This can occur because there is an incoming call on the telcoline, or because there is a previous party waiting on the telco lineafter hanging up on the cellular line through the Cel Talk/Telco WaitState 814. While in this state 803, the system will respond to the NoTelco Ring event by making a transition back to the Idle State 802. Thesystem will also respond to the Off Hook event by connecting the telcoline (which may or may not be connected already), and releasing apotential hold, and then making a transition to the Telco Talk State807.

[0068] The Cel Alert State 811 represents a condition where thetelephonic device is hung up and ringing due to a party on the cellularline. This can occur because there is an incoming Cel Alert, or becausethere is a previous party waiting on the cellular line after hanging upon the telco line through the Telco Talk Cel Wait State 813. While inthis state 811, the system will respond to the Cel not Inuse event bymaking a transition back to the Idle State 802. The system will alsorespond to the Off Hook event by making a transition to the Cel TalkState 808.

[0069] The Fatal Error State 801 is state where the system hasdetermined that a non-recoverable error condition exists. In this state801, the system must be turned off and/or reset. This state 801 may bepotentially entered from any state capable of detecting a fatal errorcondition.

[0070] An Off Hook Timeout State 816 can occur any time the telephonicdevice is left unattended and in the off hook position. If thiscondition occurs in certain states, this state 816 will become active.While in this state 816, the only event that is allowed is the Hang Upevent which causes a transition back to the Idle State 802.

[0071] A Voltage Detect Circuit 400 shown in block form in FIG. 5 andshown in detail in FIG. 6B, detects unwanted DC voltages oncommunication path 2 prior to connecting the interface circuit to thepath. The voltage detect circuit 400 detects unwanted DC voltages byplacing a capacitance across the tip and ring of communication path 2.To determine if an unwanted voltage is present, the capacitance isallowed to charge from the unwanted voltage and subsequently discharge,on command from the microprocessor U3, through a Optically isolatedsensing network. The sensing network develops a logic signal input to201 indicating the presence or absence of voltage. Referring now to FIG.6B, the circuit consists of resistors 1-5, diodes 7 and 8, capacitor 6,transistor 11, and opto-isolators 9 and 10. The function is as follows:

[0072] The tip 128-C and ring 128-D of communication path 2 areconnected to inputs T2 and R2 of the circuit 400 shown in block form inFIG. 5 and shown in detail in FIG. 6B. Resistors 4 and 5 form a voltagedivider across the tip and ring. Capacitor 6 is connected across 4 and 5through steering diodes 7 or 8 respectively. The conducting diode isdetermined by the polarity of any voltage present between the tip andring for communication path 2. Capacitor 6 charges through theconducting steering diode to one-half the open circuit talk batteryvoltage. The microcontroller U3 polls the charge state of the capacitorby generating a logic high (+5 VDC) from U3 P2.2 to transistor 11through current limiting resistor 1. This forces transistor 11 intoconduction, resulting in the flow of current from the +12 VDC supply,through current limiting resistor 2, and the LED (terminals 2&4) ofopto-isolator 10. The phototransistor of opto-isolator 10 conducts dueto current flow in the associated LED, allowing 6 to discharge throughcurrent limiting resistor 3 and the LED (terminals 4&2) of opto-isolator9. Current flowing in the LED of 9 forces the associated phototransistorto conduct, placing GROUND on P2.3 input of microprocessor U3. Themicrocontroller software polls the state of the input to determine thepresence of talk battery on communication path 2. If the pin state islogic high (+5 VDC), no talk battery is present. If the state is logiclow (GROUND), talk battery is present on the path.

[0073] A communication path switching circuit 406, shown in block formin FIG. 5 connects a Part 68 telephonic type device to multiplecommunication media systems ie, to a telephone line or to a cellularsystem interface. The communication path switching circuit 406, shown indetail in FIG. 6C, consists of relay 12, a transistor 13, a currentlimit resistor 14, and a diode 15. The Part 68 telephonic deviceterminals are connected to the contacts 12A -12F of relay 12. Contacts12A -12C switch one terminal of the Part 68 device between communicationpath 1 and the cellular interface. Contacts 12D, 12E, & 12F switch theother terminal. Control of 12 is accomplished by a signal frommicroprocessor U3. A logic high (+5 VDC) from U3 P2.1 is applied totransistor 13 through current limiter 14. Transistor 13 conducts uponapplication of the logic high, allowing current to flow through the coilof relay 12, changing the state of the relay and connecting the Part 68device to the cellular interface. A logic low (GROUND) from U3 P2.1 cuts13 off, terminating the coil current of 12, allowing the relay to changestate and connecting the Part 68 device to communication path 1.

[0074] A loop current detection circuit 410, shown in block form in FIG.5, detects the presence of loop current flowing on communication path 1.This circuit 410 shown in detail in FIG. 6D provides an electricallyisolated logic signal to microprocessor U3 indicating an on-hook oroff-hook condition for the Part 68 device when connected to the centraloffice via path 1. The loop current detection circuit 410 consists ofpullup resistor 16 and opto-isolator 17. The circuit functions asfollows: The loop current path between communication path 1 and the Part68 telephonic device flows through the bi-directional LED (terminals L1& T1) of opto-isolator 17. The presence of loop current (off-hookcondition) forces the phototransistor in 17 to conduct, placing a logiclow (GROUND) on input P3.0 of microcontroller U3. The absence of loopcurrent (on-hook condition) cuts off the phototransistor of 17, placinga logic high (+5 VDC) via 16 on U3 P3.0.

[0075] A DTMF (Dual Tone Multi Frequency) detection circuit 420, shownin block form in FIG. 5, couples DTMF from communication path 2 (eitherby loop voltage or loop current variations) for processing bymicroprocessor U3. The components of the DTMF Detection Circuit 420,shown in detail in FIG. 6E, consists of a DTMF decoder 18, clamp diodes19 and 20, limiting resistors 21 and 25, DC blocking capacitors 22 and24, and transformer 23. Transformer 23 is a 1:1 isolation transformerwith 600 ohm primary and secondary impedances. The primary of 23 isconnected across the tip and ring (T2 & R2) of communication path 2through capacitor 24. DTMF energy present on communication path 2 iscoupled through 24 to transformer 23 primary and across 23 to thesecondary. From transformer 23 secondary the isolated DTMF energy isrouted to the DTMF decoder 18 via resistor 25 for processing.

[0076] A dial tone detection circuit 430, shown in block form in FIG. 5,provides an electrically isolated signal to the microprocessor U3 forthe purpose of determining the presence of a dial tone signal. As shownin detail in FIG. 6F, the circuit 430 consists of resistors 26-28, and acomparator 29. A sample of the audio signal on communication path isconveyed to the inverting input of comparator 29 (pin 6) from 18,previously discussed. When the audio signal at comparator 29 pin 6exceeds the threshold established by voltage divider resistors 26 and 27at comparator 29 pin 5, the output of 29 (pin 7) changes state from alogic high (+5 VDC) to a logic low (GROUND). In the case of dial toneaudio, the logic signal takes on the form of a periodic pulse train.These logic state changes are conveyed to U3 input P3.7 for processingby the microprocessor software.

[0077] A ring signal detection circuit 440, shown in block form in FIG.5, detects the presence of a ring signal voltage or current oncommunication path 1, originating in the central office, and it providesan isolated logic level to the microcontroller indicating the occurrenceof a ringing event. As shown in detail in Fig, 6G, the components of theRing Signal Detection Circuit 440 consists of resistors 30-34, acapacitor 35, an opto-isolator 36, and comparator 37. The circuitfunctions as follows: The Central Office ringing signal is coupled fromcommunication path 1 via R1 through current limiting resistor 31, DCblocking capacitor 35, the bi-directional LED (terminals 1&2) of 36, andreturning via Ti. Application of the ringing signal to 36 causes the LEDto illuminate forcing the associated phototransistor to conduct. Theconducting phototransistor places a ground at the inverting input ofcomparator 37 pin 9 forcing the output of 37 pin 8 to a logic high (+5VDC). The termination of the central office ringing signal cuts off theLED illumination of 36, forcing the phototransistor into anon-conducting state, and placing +5 VDC on pin 9 of 37 via pull-upresistor 30. This condition results in a logic low (GROUND) output frompin 8 of 37. The logic states indicating the presence/absence of ringingsignals are conveyed to microprocessor U3 input P3.4 for processing bythe microprocessor software.

[0078] A ringer detection circuit 450, shown in block form in FIG. 5,tests to determine if a Part 68 telephonic device has been connected tocommunication path 2. Testing is accomplished by placing a test ringingsignal on the path and observing the presence of current flow in thepath due to the signal and a connected Part 68 device. The presence orabsence of the Part 68 device is transmitted to the microcontroller as alogic signal. As shown in detail in FIG. 6H, the ringer detectioncircuit 450 consists of resistors 38-46, clamp diodes 47 and 48, acomparator 49, a solid state relay 50 and a transistor 51. The circuitfunctions as follows: A test ringing signal is generated by block 203,described previously, and applied to the communication path 2. If anon-hook, Part 68 telephonic device is connected to the path, the ringingsignal forces current to flow through resistor 46, solid state relay 50,to the connected Part 68 device and the ringer signal generator 203 viaCR. Solid state relay 50 is closed and shunts 43 & 44 due to a U3 P3.2microcontroller signal applied through 40, 41 and 51. A voltage developsacross 46 due to the ringer current flow and is applied to the invertinginput (pin 2) of comparator 49 via resistor 45 and clamp diodes 47 & 48.The application of voltage to 49 forces the device output at pin 1 to alogic low state (GROUND). The output of comparator 49 pin 1 is input tothe microprocessor U3 at input P3.5 for processing. Removal of theringing signal, or the lack of an on-hook Part 68 device connected tothe path, forces 49 to a logic high state (+5 VDC).

[0079] A call hold circuit 470, shown in block form in FIG. 5, continuesloop current flow through the normal communication path 1 while the Part68 telephonic type device is disconnected from the normal communicationpath 1 and connected to cellular interface. As shown in detail in FIG.61, the call hold circuit consists of resistors 52 and 53, a transistor54, a diode 55, and a relay 56. Microprocessor U3 generates a logic high(+5 VDC) at P2.0. This signal is applied to transistor 54, via currentlimiting resistor 52, forcing 54 to conduct. Conducting transistor 54causes current to flow through the armature coil of relay 56, closingthe associated contacts. The contact closure forces loop current fromcommunication path 1 to flow through terminating resistor 53 via L1 &R1. With communication path 1 terminated in this manner, the Part 68telephonic device may be connected to cellular interface withoutterminating a call in progress on communication path 1. A logic low(GROUND) at U3 P2.0 terminates the relay 56 closure condition.

[0080] A battery control voltage circuit 480, shown in block form inFIG. 5, enables or disables the generation of voltages supplied to thePart 68 telephonic type device loop circuit. As shown in detail in FIG.6J, the battery control voltage circuit consists of resistors 57 and 58,a transistor 59, and a solid state relay 60. The circuit enables ordisables cellular interface talk battery generation as follows: A logicsignal from microprocessor U3 P3.1 controls the operation of thecircuit. The logic signal is applied to transistor 59 via current limitresistor 57. A logic high (+5 VDC) turns 59 on, closing solid staterelay 60 at terminals 4 & 6. The relay closure allows the application of−50 VDC, generated by previously described block 210 at VB, to the Part68 device. A logic low at U3 P3.1 opens relay 60 terminals 4 & 6,terminating the battery voltage connection.

[0081] The system control flow from a power on condition to a normalrunning condition is depicted by FIG. 7. A Start condition 701 is shownindicating the start of control flow from the power on condition. First,software guarantees that the talk battery control voltage is turned off(even though this is the default hardware state) by writing an activelow to U3, port P3.1 indicated by process block 702.

[0082] After the talk battery control voltage is turned off, thesoftware flow proceeds to process block 703, to test the outer telcopair. The outer telco pair is determined to be active if an active highis detected by software on U3, port P2.3, after software holds U3, portP2.2 high. Software does not hold U3, port P2.2 high before pulsing itthree times, and then holding it low, in order to discharge anypotential floating capacitance on the line. Software then proceeds tocheck if the outer pair is active indicated by decision block 704. Aprocess block 705, is executed if the outer telco pair is active inorder to display an error message through the radio, at which time, thesoftware proceeds to the Fatal Error state 706. While in the Fatal Errorstate 706, the system must be re-powered. If, however, the outer telcopair is detected as being inactive, then the talk battery voltage isturned on indicated by process block 707. Then software proceeds toprocess block 708.

[0083] The process block, item 708 indicates a software test to ensurethat at least one standard telephonic type communication device iscorrectly connected. This is done through software by applying an activehigh to U3, port P3.2 to turn on ring voltage, then applying a 20 Hzsignal to U3, port P1.5 and detecting a 20 Hz signal at U3, port P3.5.After software does this check, the ring voltage is turned off (activelow on U3, port P3.2). If the 20 Hz signal is detected, then it isassumed that at least one standard telephonic type communication deviceis correctly connected. Then software proceeds through a decision block,item 709, to process block 711. If however, there is no standardtelephonic type communication device signal seen, then softwareindicates this through the radio display 710, and loops back to theprocess block 708 until at least one standard telephonic typecommunication device is correctly connected.

[0084] When it is determined that the outer telco pair is inactive andat least one standard telephonic type communications device is correctlyconnected, software proceeds to the process block 711 to test that theinner telco pair is active. Software recognizes a telco inner pairconnection by asserting an active high on the hardware telco hold linethrough U3, port P2.0 and checking that telco loop current is present(active low on input U3, port P3.0). If telco loop current is notpresent (through decision block 712), then an error message is displayedthrough the display of the cellular telephone indicated by process block713. Then, the software proceeds directly to an idle state 714.

[0085] While a detailed description of the preferred embodiment of theinvention has been given above, it should be appreciated that manyvariations can be made thereto without departing from the spirit andscope of the invention as set forth in the appended claims. Thisinvention is not limited for use in buildings have a four conductorinternal telephone cable. The invention can be used in buildings havingany greater number of conductors in its internal telephone cable, aslong as one pair of conductors (or one internal communication channel)is not in use or can be freed from use. Furthermore, the disclosureassumes the internal telephone cable of the building is comprised ofdiscrete metallic conductors, with a pair of conductors forming acommunication path; however, it is foreseen that the internal telephonecable of the building can be coaxial, fiber optic, wireless or any otherform of communication path. In addition, there is no requirement in thisdisclosure that there be a one-to-one correspondence between internalbuilding telephone communication channels and conductors of a cable. Itis foreseen that the invention also works with any type multiplexing oftelephone channels on a single communication path.

1. In a telephonic communication system having at least onecommunication device for interconnection with a telephone network via atleast two communication media, the improvement comprising: means forcoupling the at least one communication device with the at least twocommunication media and means for individually determining theavailability of each of the at least two communication media; meansresponsive to the determining means connected to the coupling means forautomatically interconnecting the at least one communication device withthe telephone network via the available one of the communication media.2. The telephonic communication system of claim 1 in which the at leastone communication device is capable of direct connection with atelephone network via only one of the two communication media.
 3. Thetelephonic communication system of claim 1 in which one of thecommunication media is a landline telephone service.
 4. The telephoniccommunication system of claim 1 in which the other of the communicationmedia is a wireless telephone service.
 5. The telephonic communicationsystem of claim 3 in which the at least on communication device iscapable of direct connection with a telephone network via only thelandline telephone service.
 6. The telephonic communication system ofclaim 1 including at least two communication devices and in which thecoupling means concurrently interconnects one of the communicationdevices with one of the communication media and the other of thecommunication devices with the other of the communication media.
 7. In acommunication system having first and second communication paths and atleast one telephonic type communication device, the system being coupledto at least two communication networks for providing a first and secondmeans of communication, said first means of communication coupled to thefirst communication path, and the communication system having at leastone means for coupling the at least one telephonic communication typedevice to said first communication path, the improvement being: meansbetween said at least one telephonic type communication device and saidcoupling means for connecting said telephonic type communication deviceto said second communication path; and switching means coupled to saidsecond communication path and to said first and second means ofcommunication for selectively coupling said second communication path toone of said first and second means of communication.
 8. A communicationswitching system as described in claim 7 wherein said firstcommunication system is a wireline telephone line and said secondcommunication system is a wireless means of communication.
 9. Acommunication switching system as described in claim 7 wherein saidsecond communication system is a cellular means of communication.
 10. Ina communication system having a communication path and at least onetelephonic type communication device, the communication system beingcoupled to a communication network for providing a means ofcommunication, and the communication system having at least onetelephonic communication type device coupled to said communication path,the improvement being: testing means coupled to said communication pathfor testing the presence of any signal thereon; and interface meanscoupled to said communication path and said testing means and beingresponsive to said testing means for coupling said communication path tosaid communication network.
 11. A communication system comprising: acellular type interface coupled between a cellular-type transceiver anda six position telephone jack coupling means with at least fourpositions having individual conductors coupled thereto; a telephonictype device coupled to at least two of said individual conductors; andmeans coupled between said telephonic type device and said six positiontelephone jack coupling means for inverting the position of at least twoof said individual conductors to the position of two of the otherindividual conductors.